May Horticulture Hints

When May arrives, we know for certain that spring is here and that summer is on its way. Most plants are actively growing, and many flowers come into bloom.

Perennials and Annuals

Cannas and agapanthus grow tall and put on their first blooms. Lilies such as Easter lilies, tiger lilies, Oriental lilies, species lilies, daylilies, crinums, blackberry lilies, and others add immeasurably to the landscape. Gingers have come up, and some of the Curcumas have sent up spikes of their substantial bracts. Society garlic, which has been blooming since March, continues its show. Caladiums that were planted earlier continue to unfold their colorful leaves. Haemanthus (blood lily) pushes up myriad bright red flowers in a spectacular six-inch ball of color.

The black-eyed Susans come into full bloom in May. Purple coneflowers sport their first blooms of the season, and daylilies, gaillardia, summer phlox, rudbeckia, blue salvia, stokesia, verbena, and others accompany them.

Persicaria ‘Red Dragon’ and purple plectranthus ‘Mona Lavender’ (P. hybrida) promise delicate blooms and colorful foliage. Cupheas of several kinds are beginning their show. Purple heart and four-o’clocks are full-grown and doing their thing. In shady areas, hostas and ferns sport tender new leaves, and the achimenes begin to send up tiny sprouts.

Tender perennials that gardeners in the South usually treat as annuals are all abloom. Porterweed, blue daze, pentas, fanflower, and many others color the landscape. Heat-tolerant annuals lighting up the scene are ageratum, amaranthus, coleus, gomphrena, impatiens, nicotiana, portulaca, purslane, salvia, torenia, and vinca. Continue to plant heat-loving annuals, and keep them blooming vigorously by removing spent blooms. Begonias are filling out their space in containers and in the landscape. Ornamental peppers, yellow cosmos, perilla, and other reseeders come up so fast that one is kept busy potting up the extras or transplanting them to other areas of the garden.

Consider adding a few tropical plants for summer color. Depend on tropical hibiscus, mandevilla, ixora, allamanda, and many others for dependable color throughout the summer. Be aware, however, that these plants are not hardy here and will either need to be treated as annuals or moved to protected places during the winter.

Other May Beauties

The herb garden is resplendent with blossoms and scented foliages of poliomintha, toothache plant, savory, chives, cardoon, borage, self heal, and scented geraniums. Rosemary, oregano, Cuban oregano, basil, lemon balm, mints, bay, stevia, bouncing bet, perilla, pineapple sage–and too many to mention are growing vigorously.

Shrubs in their full glory are hydrangeas and gardenias. Butterfly bush (Buddleia davidii) is beginning its first flush of blooms, and chaste tree (Vitex agnus-castus) has begun to bloom. Hibiscus and lantana unfold their blossoms.

In containers and relishing their place outdoors free from the confines of the greenhouse are calliandra, abutilon, angelwing begonias, and tender plants of all descriptions. Hanging baskets of firecracker plant and hoya are blooming. Wandering Jew, Tahitian bridal veil, creeping Charlie, and other hanging baskets are growing vigorously.

For the Gardener to do

●Start rooting cuttings of coleus, basil, scented geraniums, shrimp plant, salvias, angel’s trumpets, clerodendrums, and other shrubs and perennials.

●Plant more heat-tolerant annuals in beds and containers for summer-long color. It is not too late to plant more caladiums in beds or in containers.

●Vegetables that like the summer heat, such as eggplant, okra, southern peas, pepper, and sweet potato can be planted in the garden.

●Amaryllis seeds can be harvested and planted in trays as soon as the pods split.

●Fertilize rapidly growing plants with slow-release fertilizer.

●Prune spring-blooming shrubs and trees as soon as they finish flowering.